1. Field of the Invention
This invention relates to dynamically-activated optical instruments for producing control signals. More particularly, it relates to an optical instrument which is activated by dynamic stimuli, generally by motions of an operator's body appendages, and produces signals which can control a musical instrument, a computer-operated visual game, or other devices.
2. Description of Related Art
Apparatus for producing sounds by radiation have been known in the art for a long time period. They are based on the principle of producing radiation, modifying it, sensing the modifications, and translating the same to signals, e.g., electrical,or electronic signals, which, in turn, produce musical tones. The modifications of the radiation may be produced by the motion of the operator's body in a space that is traversed by the radiation. The operator will be referred to hereinafter as "the player."
French Patent No. 72.39367 utilizes radar radiation. The player's body reflects the radiation towards a sensor and the Doppler effect is produced, which generates signals that are translated into acoustic frequencies. The music may be generated as a function of the speed of the player's motion or of his distance from the radiation source.
French Patent No. 81.06219 uses laser radiation, which surrounds a space in which the player moves and the tones are produced by the interception of a ray by the player's body.
U.S. Pat. No. 4,429,607 describes an apparatus comprising a number of light emitters and sensors adjacent thereto, tones being produced by reflecting back, e.g., by means of a finger, an emitted ray to the corresponding sensor.
WO 87/02168 describes, among other things, an apparatus applying the same tone-producing means as the above-described U.S. patent, but using retroflective elements applied to the human body to produce reflection that is stronger than random reflection, due, e.g., to the ceiling. Alternatively, random reflections are neutralized by confining both the emitted and the reflected beams within a narrow tube. The application also describes a way of producing different octaves by sensing the order in which a plurality of laser rays are intercepted by the player's body.